This invention concerns a plug device with phase selection that has a connector contact, for example as a socket contact, plug contact, or contact point of any design, that can selectively be connected electrically to the contact tap surfaces of at least two phase-transmission conductors by means of a switch integrated into the plug device and through a spring contact arm.
Such plug devices with phase selection are used particularly as plug-in connectors for track lights. In track lights, a fivepin flat cable (ground conductor, neutral conductor, and three phase conductors) is usually laid as transmission wiring in a track that is used to insert a number of lights. The ground conductor, the neutral conductor, and a specific phase conductor of the flat cable are contacted separately by a plug device for each light. The electrician has to decide on the spot which of the available phase conductors is contacted to achieve the most uniform line load possible, or for example, to guarantee the lighting of industrial shops or the like in case of the failure of one phase of the power source, by switching the installed lights over to another phase conductor.
For the electrician to be able to make this phase selection readily on the spot, one design possibility that has been proposed is to integrate a switch into the plug device, for example a rotary switch or a slide switch. However, this has the drawback that such a switch that has to be installed between the phase connector contact for the light and the contact tap surfaces of the individual phase-transmission conductors, increases the costs of the plug device to be produced by mass production, and requires substantially larger structural dimensions of the plug device, and also degrades the internal resistances inside the plug device, since the proposed selection switches always operate with an additional sliding contact.
It is therefore the purpose of this invention to provide a plug device with phase selection that can be produced economically and with small structural dimensions, with the internal resistances inside the plug device being kept as small as possible.
According to the teaching of the invention, when the connector contact of the plug device that is intended for the phase connection of the lights is made integral with a spring contact arm that can be deformed elastically by torsion and/or bending, then this unit consisting of the connector contact and the contact arm constitutes the smallest possible design of a selector switch, and at the same time it is free of any additional internal resistances, such as those otherwise familiar in a switch in the form of sliding contacts.
Possible design details of the plug device are described below in greater detail with reference to the drawings.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.